Typically, a single index structure (also known as Global Index) provided for a relational database may be a data structure/repository that includes/stores all the indexes defined/created for a given set of tables in the database. A database management system may store/house the global index in a physical area allocated in a DASD (Direct Access Storage Device) which may be referred to as the Standard Index area. The database management system may utilize various index structures, for example, B-tree+ (Balanced Binary Tree), and/or other index structures, to organize the Global Index.
An index may be created for one or more columns of the database table and may refer to the definition of one given index definition that is specifically linked to a column(s)'s data value. An index entry may refer to one entry or index value that is in the index and references a given data row(s) of the database table. Most access requests within the relational database environment are based on index access. Index access typically refers to the pre-definition of a specific access path that is created using the value of a data column(s). When data rows are added to a database table, an index entry is created in the index using the value of the predefined column(s). Once created, the database can quickly retrieve data rows that have an index entry (data column value) that matches a given request criteria.
With the growth in the amount of data rows that are indexed and the number of indexes that are created, the size of the Global Index continues to grow. As the Global Index grows in size, processing requests using the Global Index becomes more costly and requires more resources. For example, as a B-tree+ Global Index grows, the amount of processing to navigate through the index tree also grows. As such, as more index definitions and/or more data rows are added, the index overhead increases.
These and other drawbacks exist.